1. Field of the Invention
The present invention relates to a method for connecting exchanges via a packet-oriented communication network which permits voice data to be transmitted via a packet-oriented communication network without any loss of the voice quality.
2. Description of the Prior Art
Increasing global orientation of companies means that the use of telecommunication services for transmitting voice and data is constantly increasing. The result of this is that the costs caused by these telecommunication services are constantly rising and become a considerable cost factor for the companies, which therefore seek opportunities to reduce these costs. One opportunity for being able to transmit data inexpensively and on a worldwide basis is afforded by global computer networks, such as the Internet.
The U.S. patent application with the official file reference Ser. No. 08/942,592 has already proposed a method and an arrangement which enable data which is to be transmitted within the context of a voice link to be transmitted via a packet-oriented communication network, such as the Internet. To this end, the exchanges involved in a voice link are connected to the Internet via a respective Internet access unit, frequently called Telephony Internet Server TIS in the literature. In this case, the data which is to be transmitted within the context of a voice link is transmitted on the basis of the RTP protocol (Realtime Transport Protocol) in accordance with ITU-T Standard H.225.0 (International Telecommunication Union).
If compressed voice data, as used for mobile radio, for example, is transmitted, then this compressed voice data need to be decompressed in the Internet access unit, converted into the packet-oriented data format based on the RTP protocol and then compressed again for transmission at the transmitter end before transmission. Furthermore, at the receiver end, the data needs to be decompressed, converted into the original data format and then compressed again for further transmission. This frequent compression/decompression of the voice data results in corruption of the originally transmitted voice data at the receiver end, wherein the corruption sometimes is audible and, hence, perceivable as interference.
In addition, laid-open specification GB-A-2 320 396 discloses a method for transmitting voice data via a packet-oriented communication network in which data produced in the form of IP data packets are converted into AAL-2 data packets at the transmitter end for data transmission via the packet-oriented communication network. However, converting the IP data packets into AAL-2 data packets likewise suffers impairment of the voice quality.
It is an object of the present invention, therefore, to specify a method which permits voice data to be transmitted via a packet-oriented communication network without any loss of the voice quality.